Okuno, Hiroshi; Sato, Sohei; Kawakami, Takeshi; Yamamoto, Kazuya; Tanaka, Tadao
Journal of Radiation Protection and Research, 46(2), p.66 - 79, 2021/06
The nuclear accident at the Fukushima Daiichi Nuclear Power Station (NPS) of Tokyo Electric Power Company (TEPCO) was a typical one of the disastrous damages that induced evacuation of the residents around the NPS, which was triggered by the hugest earthquake and associated tsunami. This paper summarized early responses of the Japan Atomic Energy Agency (JAEA), especially of its Nuclear Emergency Assistance and Training Center (NEAT) to the off-site emergencies associated with the TEPCO's Fukushima Daiichi NPS. The paper addressed activities of emergency preparedness of the NEAT before 2011 in relevant to the TEPCO's Fukushima Daiichi NPS, the situation of the NEAT on March 11, 2011, and its early responses to the related off-site emergencies including those caused by the accident at the TEPCO's Fukushima Daiichi NPS. The paper also discussed issues associated with complex disasters.
Okuno, Hiroshi; Yamamoto, Kazuya
JAEA-Review 2020-066, 32 Pages, 2021/02
The International Atomic Energy Agency (abbreviated as IAEA) has been implementing the Asian Nuclear Safety Network (abbreviated as ANSN) activities since 2002. As part of this effort, Topical Group on Emergency Preparedness and Response (abbreviated as EPRTG) for nuclear or radiation disasters was established in 2006 under the umbrella of the ANSN. Based on the EPRTG proposal, the IAEA conducted 23 Asian regional workshops in the 12 years from 2006 to 2017. Typical topical fields of the regional workshops were nuclear emergency drills, emergency medical care, long-term response after nuclear/radiological emergency, international cooperation, national nuclear disaster prevention system. The Japan Atomic Energy Agency has produced coordinators for EPRTG since its establishment and has led its activities since then. This report summarizes the Asian regional workshops conducted by the IAEA based on the recommendations of the EPRTG.
Togawa, Orihiko; Hayakawa, Tsuyoshi; Tanaka, Tadao; Yamamoto, Kazuya; Okuno, Hiroshi
JAEA-Review 2020-017, 36 Pages, 2020/09
In 2010, the government of Japan joined the Response and Assistance Network (RANET) of the International Atomic Energy Agency (IAEA), in order to contribute to offering international assistance in the case of a nuclear accident or radiological emergency. At that occasion, the Japan Atomic Energy Agency (JAEA) was registered as the National Assistance Capability (NAC) having resources capable of the External Based Support (EBS) in the following seven areas: (1) aerial survey, (2) radiation monitoring, (3) environmental measurements, (4) assessment and advice, (5) internal dose assessment, (6) bioassay and (7) dose reconstruction. After the registration, three inquiries were directed to the JAEA about a possibility of its support. However, the JAEA's assistance has not eventually been realized. On the other hand, the JAEA participated almost every year in the international Convention Exercise (ConvEx) carried out by the IAEA in connection with RANET. This report describes an outline of the RANET and related activities of the JAEA for RANET registration and participation in the ConvEx.
Okuno, Hiroshi; Okamoto, Akiko; Ebine, Noriya; Hayakawa, Tsuyoshi; Tanaka, Tadao
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 15 Pages, 2019/05
In the event of a nuclear or radiological emergency, the Japan Atomic Energy Agency (JAEA) as a designated public corporation assigned in the Disaster Countermeasures Basic Act of Japan undertakes a role to support the national government and local governments. This paper (1) illuminates the roles of the JAEA as a designated public corporation for preparedness and response to a nuclear or radiological emergency of nuclear facilities; (2) summarizes emergency response activities of the JAEA in accordance with its Disaster Management Operation Plan against the off-site radiological emergencies attributed to a loss of control of the Tokyo Electric Power Company (TEPCO)'s Fukushima Daiichi Nuclear Power Station that occurred in 2011; and (3) reports its activities in normal times especially participation in the drills organized by the national government and local governments in the light of the Basic Disaster Management Plan of Japan and Local Disaster Management Plans of prefectural governments, respectively.
Okuno, Hiroshi; Suyama, Kenya; Ryufuku, Susumu*
JAEA-Review 2017-010, 93 Pages, 2017/06
There is an ongoing discussion on the application of burnup credit to the criticality safety controls of facilities that treat spent fuels. With regard to such application of burnup credit in Japan, this document summarizes the current technical status of the prediction of the isotopic composition and criticality of spent fuels, as well as safety evaluation concerns and the current status of legal affairs. This report is an English translation of A Guide to Introducing Burnup Credit, Preliminary Version, originally published in Japanese as JAERI-Tech 2001-055 by the Nuclear Fuel Cycle Facility Safety Research Committee.
Watanabe, Fumitaka; Okuno, Hiroshi
Proceedings of 18th International Symposium on the Packaging and Transport of Radioactive Materials (PATRAM 2016) (DVD-ROM), 9 Pages, 2016/09
This paper shows our calculations on the effects of a radiological release by assuming a severe accident in nuclear material transportation. Following recalculations of safe distance from the point of a severe accident during transportation of a transportation cask TN12 typically used in France containing spent nuclear fuel, and calculations to replicate the "Regulatory Guide: Emergency Preparedness for Nuclear Facilities", a similar calculation was made for a spent fuel transportation cask NFT-14P that was typically utilized in Japan instead of TN12. The safe distance was calculated to be about 30 m. The above calculations were made with the HotSpot codes which adopted the Gauss plume model and had been developed by the USA. Some additional calculations were made with EyesAct, which was developed and used in Japan, adopting also the Gauss plume model, to compare calculation results.
Nakajima, Ken*; Itahara, Kuniyuki*; Okuno, Hiroshi
Proceedings of International Conference on Nuclear Criticality Safety (ICNC 2015) (DVD-ROM), p.496 - 502, 2015/09
An outline of the standard "Procedures for Applying Burnup Credit to Criticality Safety Control of a Reprocessing Facility: 2014" (AESJ-SC-F025: 2014) published in April 2015 by the Atomic Energy Society of Japan (AESJ) is presented. The AESJ published more than 60 Standards. However, many of them were in the field of nuclear power reactors or radioactive wastes. Ten years ago the AESJ published "Basic Items of Criticality Safety Control: 2004" (AESJ-SC-F004:2004), which prescribed basic ideas, requirements and methods on nuclear criticality safety controls of facilities handling with nuclear fuel materials in general for preventing a nuclear criticality accident. However, it did not include any specific procedures for adopting burnup credit. Therefore, a new standard was envisaged as the first Standard for fuel reprocessing plants, which clarified the specific procedures to apply burnup credit to designers, operators, maintenance persons and administrators.
Ozeki, Hidemasa; Isono, Takaaki; Kawano, Katsumi; Saito, Toru; Kawasaki, Tsutomu; Nishino, Katsumi; Okuno, Kiyoshi; Kido, Shuichi*; Semba, Tomoyuki*; Suzuki, Yozo*; et al.
IEEE Transactions on Applied Superconductivity, 25(3), p.4200804_1 - 4200804_4, 2015/06
Sukegawa, Atsuhiko; Iida, Hiromasa*; Itoga, Toshio*; Okumura, Keisuke; Kai, Tetsuya; Konno, Chikara; Nakashima, Hiroshi; Nakamura, Takashi*; Ban, Shuichi*; Yashima, Hiroshi*; et al.
Hoshasen Shahei Handobukku; Kisohen, p.299 - 356, 2015/03
no abstracts in English
Sato, Takeshi; Muto, Shigeo; Akiyama, Kiyomitsu; Aoki, Kazufumi; Okamoto, Akiko; Kawakami, Takeshi; Kume, Nobuhide; Nakanishi, Chika; Koie, Masahiro; Kawamata, Hiroyuki; et al.
JAEA-Review 2014-048, 69 Pages, 2015/02
JAEA was assigned as a designated public institution under the Disaster Countermeasures Basic Act and under the Armed Attack Situations Response Act. Based on these Acts, the JAEA has the responsibility of providing technical support to the national government and/or local governments in case of disaster responses or response in the event of a military attack, etc. In order to fulfill the tasks, the JAEA has established the Emergency Action Plan and the Civil Protection Action Plan. In case of a nuclear emergency, NEAT dispatches specialists of JAEA, supplies the national government and local governments with emergency equipment and materials, and gives technical advice and information. In normal time, NEAT provides various exercises and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response institutions of the national and local governments, police, fire fighters, self-defense forces, etc. in addition to the JAEA itself. The NEAT also researches nuclear disaster preparedness and response, and cooperates with international organizations. In the FY2013, the NEAT accomplished the following tasks: (1) Technical support activities as a designated public institution in cooperation with the national and local governments, etc. (2) Human resource development, exercise and training of nuclear emergency response personnel for the national and local governments, etc. (3) Researches on nuclear disaster preparedness and response, and sending useful information (4) International contributions to Asian countries on nuclear disaster preparedness and response in collaboration with the international organizations
Okuno, Koichi*; Iikura, Hiroshi
Nuclear Science and Techniques, 25(S1), p.S010604_1 - S010604_5, 2014/12
no abstracts in English
Sato, Takeshi; Muto, Shigeo; Okuno, Hiroshi; Katagiri, Hiromi; Akiyama, Kiyomitsu; Okamoto, Akiko; Koie, Masahiro; Ikeda, Takeshi; Nemotochi, Toshimasa; Saito, Toru; et al.
JAEA-Review 2013-046, 65 Pages, 2014/02
When a nuclear emergency occurs in Japan, the Japan Atomic Energy Agency (JAEA) has the responsibility of providing technical support to the National government, local governments, police, fire stations and nuclear operators etc., because the JAEA has been designated as the Designated Public Institution under the Basic Act on Disaster Control Measures and the Act on Response to Armed Attack Situations, etc.. The Nuclear Emergency Assistance and Training Center (NEAT) of JAEA provides a comprehensive range of technical support activities to an Off-Site Center in case of a nuclear emergency. Specifically, NEAT gives technical advice and information, dispatches specialists as required, and supplies the National Government and local governments with emergency equipments and materials. NEAT provides various exercise and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response organizations at normal times. The tasks of NEAT, with its past experiences as a designated public institution including the responses to TEPCO's Fukushima Accident, have been shifted to technical supports to the national government for strengthening its abilities to emergency responses; the NEAT therefore focused on maintenance and operation of its functions, and strengthening its response abilities in cooperation with the national government. This annual report summarized these activities of JAEA/NEAT in the fiscal year 2012.
Nakanishi, Chika; Sato, Takeshi; Sato, Sohei; Nagai, Haruyasu; Kakefuda, Toyokazu; Katata, Genki; Tsuzuki, Katsunori; Ikeda, Takeshi; Okuno, Hiroshi; Yamamoto, Kazuya; et al.
JAEA-Technology 2013-030, 105 Pages, 2013/10
North Korea carried out the third nuclear test in February 2013. Due to the request of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Nuclear Emergency Assistance and Training Center (NEAT) and Nuclear Science and Engineering Directorate (NSED) of JAEA predicted the atmospheric dispersion of radionuclide by WSPEEDI-II for the purpose of contributing to the environmental monitoring plan. From February 12 to 22, they provided daily reports on the prediction to the MEXT and the Ministry of Defense. MEXT has published these reports on the website. Since April 2012, NEAT and NSED had prepared to predict by the framework for the prediction around the clock during 10months until February 2013. This report described this experience and pointed issues out on this system.
Katagiri, Hiromi; Okuno, Hiroshi; Okamoto, Akiko; Ikeda, Takeshi; Tamura, Kenichi; Nagakura, Tomohiro; Nakanishi, Chika; Yamamoto, Kazuya; Abe, Minako; Sato, Sohei; et al.
JAEA-Review 2012-033, 70 Pages, 2012/08
When a nuclear emergency occurs in Japan, JAEA has the responsibility of providing technical support to the National government, local governments, etc., by the Basic Law on Emergency Preparedness and the Basic Plan for Disaster Countermeasures. NEAT of JAEA gives technical advice and information, dispatch specialists as required, supplies with the National Government and local governments emergency equipment and materials. NEAT provides various lectures and training courses concerning nuclear disaster prevention for emergency response organizations at normal time. Concerning the assistance to the Accident of Fukushima No.1 Nuclear Power Station caused by the Great East Japan Earthquake on 11 March, 2011, JAEA assisted activities including environmental radiation monitoring, environmental radioactivity analyses, resident public consulting etc., with its the utmost effort. This annual report summarized these activities of NEAT in the fiscal year 2011.
Tonoike, Kotaro; Suyama, Kenya; Okuno, Hiroshi; Miyoshi, Yoshinori; Uchiyama, Gunzo
Proceedings of 9th International Conference on Nuclear Criticality (ICNC 2011) (CD-ROM), 8 Pages, 2012/02
The 1st version of criticality safety handbook of Japan was published in 1988. A criticality safety analysis code system JACS was validated, and minimum critical mass and safety limit mass of various fissile materials were calculated. During more than two decades since then, new critical experimental data were taken in the Static Critical Experiment Facility (STACY), and more precise benchmark data of wider range of fissile materials were accumulated by the International Criticality Safety Benchmark Evaluation Project (ICSBEP). Computational capability has greatly grown, and new codes and nuclear data have been developed. The 2nd version of the handbook utilizes the results of validation of the criticality analysis method with a continuous energy Monte-Carlo code MVP and a nuclear data library JENDL-3.2 using the benchmark data chosen from the ICSBEP handbook. Results of the benchmark calculation were statistically studied, from which the safety limit value of multiplication factor was derived as 0.98. Based on the conclusion, minimum critical mass and safety limit mass were calculated. Future plan of research activities on the criticality safety in JAEA will be also overviewed.
Katagiri, Hiromi; Okuno, Hiroshi; Sawahata, Masayoshi; Ikeda, Takeshi; Sato, Sohei; Terakado, Naoya; Nagakura, Tomohiro; Nakanishi, Chika; Fukumoto, Masahiro; Yamamoto, Kazuya; et al.
JAEA-Review 2011-037, 66 Pages, 2011/12
When a Nuclear emergency occurs, Nuclear Emergency Assistance & Training Center (NEAT) of JAEA gives technical advice and information, dispatch specialists as required, supplies emergency equipment and materials to the National Government and local governments. NEAT provides various lectures and training courses concerning nuclear disaster prevention for those personnel taking an active part in emergency response organizations at normal time. NEAT also researches on nuclear disaster prevention and cooperates with international organizations. Concerning about the assistance to the Accident of Fukushima No.1 Nuclear Power Station caused by the Great East Japan Earthquake at 11 March, 2011, JAEA assisted activities including environmental radiation monitoring, environmental radioactivity analyses, resident public consulting etc., with its full scale effort. NEAT served as the center of these supporting activities of JAEA.
Kanamori, Masashi; Shirakawa, Yusuke; Yamashita, Toshiyuki; Okuno, Hiroshi; Terunuma, Hiroshi; Ikeda, Takeshi; Sato, Sohei; Terakado, Naoya; Nagakura, Tomohiro; Fukumoto, Masahiro; et al.
JAEA-Review 2010-037, 60 Pages, 2010/09
When a nuclear emergency occurs in Japan, the Japan Atomic Energy Agency (JAEA) provides technical support to the National government, local governments, police, fire station and license holder etc. They are designated public organizations conforming to the basic law on emergency preparedness and the basic plan for disaster countermeasures. The Nuclear Emergency Assistance & Training Center (NEAT) of JAEA provides a comprehensive range of technical support activities to an off-site center in case of a nuclear emergency. Specifically, NEAT gives technical advice and information, provides for the dispatch of specialist as required, supplies emergency equipments and materials to the national government and municipal office. NEAT provide various lectures and training course concerning nuclear disaster prevention for those personnel taking an active part in emergency response organizations at normal time. And NEAT researches on nuclear disaster prevention and also cooperate with international organizations. This annual report summarized the activities of JAEA/NEAT in the fiscal year 2009.
Okuno, Hiroshi; Sato, Shohei; Kawasaki, Hiromitsu*
Journal of Nuclear Science and Technology, 46(12), p.1137 - 1144, 2009/12
The critical concentrations of metal-SiO and -HO mixtures were calculated for 26 actinides including U, Pu, Am, Cm and Cf, where the critical concentration was defined as the concentration that the infinite neutron multiplication factor, k being calculated to be 1.0. The calculations were performed using the Monte Carlo neutron transport calculation code MCNP5 combined with the evaluated nuclear data library JENDL3.3. The results showed that the critical actinide concentration of metal-SiO was ca. 1/5 of that of metal-HO for all the fissile nuclides investigated. The k's of the metal-SiO and metal-HO at a half of the respective critical actinide concentration, which concentration was assumed as the subcritical actinide concentration limit, were found to be less than 0.8 for all the actinides considered. Applying a sum-of-fractions rule with respect to the ratios of actinide concentration to the subcritical actinide concentration limit for six fissile nuclides, subcriticality of high-level radioactive wastes was confirmed for a reported sample. The effect of different nuclear data libraries on the results of critical actinide concentrations was found large for Cm, Cm and Cf.
Sato, Shohei; Okuno, Hiroshi
JAEA-Data/Code 2009-014, 19 Pages, 2009/11
The estimated criticality lower limit multiplication factor (hereafter, ECLLMF) is the upper limit of the neutron multiplication factor where the system may be judged subcritical through the calculation results of the same criticality calculation system applied to analogous fuel systems to be evaluated. Aiming to establish an effective method to find the rational ECLLMF of mixed uranium and plutonium oxide (MOX) fuel systems, this report investigated the classification of the critical experiments for the statistical processing, and evaluated the calculation errors with considering the dependence on Pu isotopic fraction within the classified experiments. In this evaluation, the criticality calculation code MVP and the evaluated nuclear data library JENDL-3.3 library were utilized, and the criticality experiments with MOX fuels registered in the international criticality safety benchmark evaluation project (ICSBEP) handbook were adopted. It was found that the dependency of the benchmark calculation results on the Pu isotopic fraction was enhanced by introducing a new fuel class: "dual heterogeneous fuel systems." As a result of this classification and error evaluation, it was confirmed that the calculated values of all the ECLLMFs were below the benchmark calculation results, and that the value of the ECLLMF was high compared with that obtained with the traditional method.
Okuno, Hiroshi; Suyama, Kenya; Tonoike, Kotaro; Yamane, Yuichi; Yamamoto, Toshihiro; Miyoshi, Yoshinori; Uchiyama, Gunzo
JAEA-Data/Code 2009-010, 175 Pages, 2009/08
The report revised the Data Collection part of Nuclear Criticality Safety Handbook, which was published in 1988. This second version provided criticality data on homogeneous U-HO and UF-HF, which were not cited in the previous version, and increased those data on the medium-enriched uranium fuels. Calculations were performed mainly with the Continuous-Energy Monte Carlo Criticality Calculation Code, MVP, and the Japanese Evaluated Nuclear Data Library, JENDL-3 Revision 2, JENDL-3.2, both of which were developed at the late Japan Atomic Energy Research Institute (JAERI). Data on atomic number densities of actinide metal and oxide were additionally supplied, and nuclide compositions of irradiated fuels were improved from the first version. One million histories of neutrons were followed in benchmark calculations of critical experiments and in calculations of single-unit criticality data, i.e., critical mass, volume, dimensions, etc., to attain almost ten times higher precision than the first version.